Any CNET Video Podcast. Say "Apple Byte". I can download it on my Computer using iTunes and sync to my iPhone and play it no problem.
However, if on my iPhone I click on "Get More Episodes" and download the latest episode from within the iTunes application, the resulting podcast won't play. Yes I watch it download the whole thing, but it acts like its 0 seconds long. Click on the podcast and the player comes up then immediately vanishes then returns to the podcast list again.
Happens with ALL of the CNET Video Podcasts as far as I can tell. Works fine with all of the audio ones.
With other providers, say TWiT, I can download the video podcasts on the go no problem. Not sure who's fault this is or what can be done to fix it. Anybody got any ideas?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic